This invention relates in general to multiple disc friction clutches and in particular to an adapter clip for updating an older style clutch cover for use with an intermediate plate positioning means.
Clutches are well known devices which are used to selectively connect a source of rotational power, such as the crankshaft of an engine, to a driven mechanism, such as a transmission or a power take-off unit. Typically, a cover of the clutch is connected to a flywheel carried on the end of the engine crankshaft for rotation therewith. Between the flywheel and the clutch cover, a pressure plate is disposed. The pressure plate is connected for rotation with the flywheel and the cover, but is permitted to move axially relative thereto. A shift lever assembly is provided for selectively moving the pressure plate back and forth in the axial direction.
A driven disc is disposed within the clutch between the pressure plate and the flywheel. The driven disc is carried on an output shaft of the clutch, which forms the input to the transmission or the power take-off unit. When the pressure plate is moved toward the flywheel, the driven disc is frictionally engaged therebetween so as to cause the output shaft of the clutch to rotate with the flywheel, the cover, and the pressure plate. When the pressure plate is moved away from the flywheel, the driven disc is released from such frictional engagement so as to disconnect this driving connection.
The ability of the clutch to transmit torque from the flywheel to the output shaft may be increased by using more than one driven disc as described above. In a multiple disc clutch, an intermediate plate is disposed between the flywheel and the pressure plate. As with the pressure plate, the intermediate plate is connected for rotation with the flywheel and the cover of the clutch, while being permitted to move axially relative thereto. A first driven disc is disposed between the pressure plate and the intermediate plate, while a second driven disc is disposed between the intermediate plate and the flywheel. The operation of the multiple disc clutch is similar to that described above.
When the pressure plate is moved away from the flywheel to release the frictional engagement of the driven discs, it is desirable that the intermediate plate be positioned equidistantly between the two driven discs to prevent undesirable wear. In the past, multiple disc clutches were not provided with any means for positioning the intermediate plate in this manner. However, it is now common to provide such a means, and various positioning mechanisms are known for accomplishing this. Many of these positioning mechanisms include the use of pins frictionally supported in axially extending apertures formed through the outer periphery of the intermediate plate. The forward ends of the pins are adapted to abut the flywheel when the driven discs are frictionally engaged, while the rearward ends of the pins are adapted to abut an abutment surface formed on the cover when the driven discs are released. As wear occurs within the clutch, the pins are moved axially relative to the intermediate plate to continuously re-position the intermediate plate such that it remains equidistant between the driven discs when the clutch is disengaged. An example of such an intermediate plate positioning means is disclosed in U.S. Pat. No. 4,941,557 to Flotow et al., owned by the assignee of this invention.
As mentioned above, some older multiple disc clutches were not provided with any means for positioning the intermediate plate equidistantly between the two driven discs. When such older clutches are removed from service for periodic maintenance, it has been found to be desirable to update them to include an intermediate plate positioning means. In theory, such updating can be accomplished in a relatively simple and inexpensive fashion, because the older style intermediate plate (having no apertures or positioner pins) needs only to be replaced with a newer style intermediate plate (having such apertures and positioner pins).
Unfortunately, in actual practice, a problem has arisen which complicates this updating process. The problem is that the covers of such style older clutches were not designed to provide any convenient abutment surface for the positioner pins, as described above. It is known to weld bosses onto these older covers in appropriate locations to provide the required abutment surface. However, this has proven to be a time consuming and somewhat inefficient task. Thus, it would be desirable to provide an adapter clip which can be quickly and easily attached to an older style cover to provide the necessary abutment surface, allowing the cover to be used with the intermediate plate positioner pins.